“What are those jellyfish in the water?!”
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Every spring and early summer, Nova Scotia gets a group of fabulous visitors in our waters. I have seen so many people hanging their head over the side of the Halifax boardwalk trying to get a better look at these tiny mysteries. But today we are breaking the mystery for you. So what are they? They go by many names including ‘disco jellies’, ‘ctenes’, or ‘comb jellies’, but their mouthful of a scientific name is Ctenophora. [Pronounced “teen-OH-four-ah”]. Now these extravagant little jellies are many things but the one thing they are not is jellyfish!

While Ctenophora may have the gelatinous form we are used to seeing in ‘jellyfish’ (which is classified scientifically at Cnidiarians), there are a few hallmark reasons that make them their own phylum and a very fun animal to observe:

Don’t fear! Ctenophora can’t sting you. This is one of the most noteworthy differences between Ctenophora and Cnidarians (aka jellfyfish!). They do not have what are called cnidocytes which deliver the stringing feeling we get when we touch the tentacles of a jellyfish. However, even though they can’t sting you we still recommend observing them at a safe distance. Since ctenophora have a soft jelly-like body it is very easy to injure these little wonders.

How do they get around? I am so glad that you asked! Ctenphora are the largest organisms that move by ‘cilia’. Cilia are very tiny hairs that typically bacteria use to move around. Ctenophora have eight rows of the cilia attached to their body which move in tandem to help them get around. Slow and steady wins the race with ctenes! See how they move here. 

Hey! Why do they look different? Both of these pictures are ctenophora, but are different species. Ctenophora really do come in all shapes and sizes. Ctenophora have lots of different species and some have beautiful long tentacles and some are nice and oval shaped without any additional appendages. Often in Nova Scotia, we have multiple different species of ctenohpora in our waters at the same time.

What is the RAINBOW? Ctenophora are often mistaken are being “bioluminescent” which is the process where organisms give off their own light. Now some species of Ctenophora are biolumensect, but most often if you are seeing beautiful rainbow colours it is from the light refracting off the tiny beating cilia! We love to call them disco jellies for this reason! What do you think their favourite disco song is to synchronously move their rows of cilia to? (My bet is on Stayin’ Alive!).

by Kayla Hamelin

When you live in Nova Scotia, it is obvious that fishing is an important part of the culture and economy of Atlantic Canada. Fishing vessels fill our harbours. Folks head down to their local pier – rod in hand - to cast a line and see what bites. Seafood restaurants and markets abound. People fish for fun, for food, and for work. 

​Mackerel are a marine, pelagic fish, which means that they live in the open water column of the ocean, rather than on the bottom or at the shore. They have beautiful bodies well-adapted for camouflage in the ocean, with shimmery blue on their backs, silvery undersides, and squiggly stripes down their backs and flanks. You may notice the tiny finlets (mini, nonretractable fins) on their caudal peduncle (a funky name for the area where the body meets the tail fin). These finlets help with their high-performance swimming and are a feature shared with some of the larger members of their Scombridae family, including the mighty tunas and bonitos. 

Mackerel are relatively small, measuring up to about 40 cm (a bit more than a foot) in length and about 1 kg in mass. However, there is strength in numbers, and these schooling fish like to swim together in large groups to stay safe from predators. Fun fact: unlike many of their relatives, mackerel do not have a swim bladder, the gas-filled organ that helps many fish to control their buoyancy. Without a swim bladder, mackerel must follow Dory’s advice and just keep swimming!

​​Unfortunately, Fisheries and Oceans Canada has classified mackerel in the critical zone, meaning that the stock has declined and needs rebuilding. However, we still don’t know a lot about the biology, ecology, and fishery operations for Atlantic mackerel. I think this seems like a great oppor-tuna-ty for fishers, scientists, and government officials to unite and work together to ensure that an abundance of these creatures can be found swimming our seas for years to come. If you’re interested in chatting all things mackerel, feel free to reach out at kayla.hamelin@dal.ca!
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By Alex Tesar
 
We here at the Back to the Sea Society hate to be accused of favouritism. When it comes to marine life, we love it all, from anemones to zooplankton. Jellyfish: yes. Whales—whale, of course. But there is one group of animals that may be entitled to bear the crown of nature’s most perfect creature. I speak, of course, of crabs.
 
To understand why, we must first look at some things that aren’t crabs. Sorting the crabs from the crab-nots can be complicated. Consider, for example, the hermit crab: protruding eyes on stalks, a shell, and the trademark claws that suggest the quintessence of crabbiness. You would be forgiven for thinking that you were looking at a crab.
 
However, despite their name, hermit crabs aren’t actually crabs. Though they resemble “true crabs,” hermit crabs are in fact a different kind of crustacean that happens to look very similar. And they are far from alone: among those living in disguise are the king crabs, which may have themselves evolved from hermit crabs (known, delightfully, as the “hermit-to-king” hypothesis), as well as hairy stone crabs and porcelain crabs. 
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The king crab is not a crab, but it is a king. 
Photo credit: NOAA Office of Ocean Exploration and Research, Gulf of Mexico 2017

​The theory that crab-like crustaceans tend to evolve from non-crab ancestors is known as “carcinization.” The word literally means to become cancer-like, but think of the astrological sign, not the disease. The phenomenon was first described by a man named Lancelot Alexander Borradaile, who has perhaps one of the best names in the history of science. Borradaile coined the term while studying the evolution of the humble hermit crab, describing it as “one of the many attempts of Nature to evolve a crab.”
 
Why does Nature want to evolve a crab so badly? Well, we know that evolution “selects” for traits that are particularly well-suited to a given environment, and there seems to be something about the crab-like shape that works very well when it comes to surviving and thriving in the water—so what works for “true crabs” might also evolve in other species that aren’t close genetic relatives. This is called parallel evolution.
 
There are other examples of this in nature, too. In Australia, many marsupial species have evolved separately from mammals in the rest of the world but still look strangely familiar because they’ve faced similar evolutionary pressures—like the flying phalanger and the flying squirrel, which both glide from tree to tree. 

​It appears that nature likes to get crabby. Of course, there’s no such thing as a perfect animal in evolution, only the creature that’s best adapted to its time and place. But when you come to the touch tank this summer, you can get hands-on and decide for yourself whether you are simply holding a hermit crab or touching a miracle. 

by Alisha Postma

When you live and breath scuba diving, sooner or later you’re going to get the opportunity to dive into some pretty neat spots all over the world. Iceland, Greece, Egypt, Florida…

My exotic scuba diving list is pretty extensive, but truth be told, as beautiful and picturesque as these dive destinations may be, as a Canadian diver, there is no place like home.

For the past 6 years, I have lived in Halifax, Nova Scotia.

Located on Canada’s east coast, Nova Scotia is the second smallest of ten provinces. It’s also a peninsula that is pretty much surrounded by Atlantic ocean. For cold water divers it’s paradise, and guess what? I’m proud to say it’s my paradise too!

When you first look out into the North Atlantic it can be a bit unsettling. Cold, darkness, less than ideal visibility are a few things that immediately come to mind. But it only took me a few dives to figure out why when looking into our own backyards we can’t see the bottom - it’s because it’s so full of life.

Ready to have your mind blown by the Canadian North Atlantic?

​It’s common to spot sculpin and sea ravens in the waters of Nova Scotia. This ruby red sea raven was photographed at the Paddy’s Head dive site, a favorite among the locals.
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With their dainty colors and itty-bitty bodies, nudibranchs are always a fun subject for macro shooters. While you can find nudi’s to shoot in Nova Scotia if you look really hard, they are much easier to find on Deer Island, New Brunswick.
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When photographing in Nova Scotia, I like to look for small critters like this funky little spiny lumpsucker. It gives the dive site some personality.
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Keep your eyes peeled because you never know what you will spy in the plant life. This rock crab decided to peek out for me on the green dead man’s fingers (scientifically known as Codium fragile).
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Striking red and pink colours are a sight for sore eyes in the cold productive waters of the Bay of Fundy. Here you will find brightly coloured anemones of all different shapes and sizes, with tentacles out trying to catch some food from the water column!  
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Nothing spells Nova Scotia better than a close-up view of a lobster. You can find these arthropods all over the east coast scavenging the bottom on the hunt for their next meal. I love grabbing macro shots of these guys with a focal point on their beady little eyestalks.

Plant, animal or lifeless rock?

Chitons, also known as sea cradles, are a species of mollusk found exclusively in marine environments. On top of having the incredible power of surface adhesion, chitons have 8 separate shell plates that overlap and protect their otherwise soft body.
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by Leah Robertson

On both land, and in the ocean we are thankful for great dads! However, when we think of fish in the ocean, fish parental care may not immediately come to mind. But dads play a huge role in taking care of their offspring in the ocean!
 
So in honour of father’s day, we have chosen two special fish-dads to highlight! Meet the rock gunnel:

​This lil guy is often mistaken for an eel, but they are much smaller than that - only growing to 30cm! In this photo, father rock gunnel is guarding a cluster of eggs which are in the back of this very clever home - a bottle!
 
 
Our second dad is the 3-spined stickleback, who will teach us all about the ways fish act as fathers. 

​This little fish can be found in our local fresh, coastal and brackish waters.  They can be characterized by three tiny spikes on the top and the persistence of being a great father!

​The males of this fish work hard to build their nest to attract females, when their off springs are just a twinkle in their eye! They work to build these nests by digging a small pit, and then filling it with cozy ocean objects like algae to make it just right. After building their nest, they will do a zigzag dance to attract the female (seriously true!). If the fit is right, the soon to be momma will swim into the nest and lay her eggs. From there on out dad takes over in protecting the eggs, from fanning them often to creating little holes to ensure they are well ventilated soon to be tiny fish. Once the sticklebacks do hatch, dad will try to keep them around for a few days and if any try to wander away he will suck them up with his mouth and spit them back out near the nest. Talk about committed!  
 
We are whaley thankful for dads both on land and in the ocean!


P.S. Special Father’s Day shout out to my own dad!

​It doesn’t happen regularly, but every once in a while, you will come across an animal that leaves you truly perplexed. There are animals that hold hands, throw punches, mimic leaves, change sexes, have two jaws, regenerate limbs, and have cube-shaped poop. If we were to rank* the perplexities that exist in the animal kingdom however, the top spot would belong to the cuTTlefish**. Not only do they have three hearts and can mimic the shape and texture of their surroundings, but they can also count better than human babies! For these reasons alone, cuTTlefish deserve to be a top contender for the prestigious Perplexity Prize but they have another surprising trick up their tentacle that really sets them apart.

​Male cuTTlefish compete with one another to catch the attention of females in the hopes of mating with them. These competitions can be very aggressive and often involve barrel rolls, squirts of black ink, and an exchange of bites using hardened beaks. As is the case in many similar debacles, the larger male generally wins the fight. Ironically however, their efforts and injuries may not lead to a successful mating opportunity with observing females. This is because small male cuTTlefish are able to sneak past the fighting males by disguising as a female. The steps to doing so are pretty straightforward, (1) mimic muted female colours, (2) tuck in their tentacles to appear as if they are carrying eggs, and (3) rely on their smaller size. Once they get past the larger competitive males, the smaller males will reveal themselves to the females by turning on a colourful display and, well, you know what happens next.

So, there you have it, an animal whose perplex, peculiar, and puzzling abilities are worthy or recognition and celebration. I challenge you to embody the cuTTlefish – the ultimate trickster – on this special day. I myself, am looking forward to challenging babies to counting contests.
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* Every animal is beautiful and unique in its own way
** Although I cannot comment about whether these animals like cuddling, I can confirm that these animals are not referred to as cuddlefish 

​​When it is raining, I take out my boots and jacket. When it is snowing, I add a scarf and some mittens. When it is windy, I increase my layers and quicken my steps. It is safe to say, that since I moved to the Maritimes, I have adapted to the changing – often unexpected – weather conditions.

​My usual response to downpours, blizzards, and wind storms is to stay inside with a bag of storm chips and peak out the window to see how nature is fairing. My view consists of trees, buildings, and the unfortunate person that didn’t reach shelter in time. What I can’t see from my window during these weather events is the ocean, but I can envision the swell and the crashing waves. What is harder to imagine is how our beloved ocean organisms survive – animals and algae alike!

​​​The intertidal zone in Nova Scotia is characterized by things like crabs, snails, mussels, barnacles, and rockweed. These animals are not often described as being hardy, but they should be, as their adaptations allow them to survive in a very volatile environment. The environment is difficult because not only do these animals have to deal with stressors that originate in the ocean, but they also must worry about what comes from the land and atmosphere – eek! Some animals, like crabs, find protection by hiding in cracks or under boulders while others, like snails, carry protection on their back. 

​​If we were to move deeper into the subtidal, not only would the organisms change, but so would the impact of weather events. If the seabed is further from the ocean surface, it is less impacted by the weather – think of the depth as a kind of buffer zone. Since the organisms are less impacted, they do not dedicate as much energy into weather-protective adaptations. You still see adaptations however; sea stars don suction cup-like tube feet and other benthic invertebrates remain streamlined. The organism’s primary concern in the subtidal, unlike the intertidal, is not to adapt to weather but instead put energy into fleeing predators and finding food – how cool!

​If we were to go deeper in the ocean you may notice some differences that exist between that ecosystem and the one that exists in the intertidal and the subtidal. First off, it is dark, I mean no-sun-is-penetrating dark, and it is cold. What you will not notice however, is sloshing water caused from overhead weather events. Other than debris falling from surface waters, there would be no evidence of a weather event because wave energy does not attenuate deep enough to impact the organisms that live there.

So, my advice to you is if you really want to escape Maritime weather events you should hop, skip, and jump to the bottom of the ocean.

​Happy splashing!
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This Valentine's Day, our Communications Committee members came together to let their favourite ocean animals know just how much they care for them. Read on for some pun-filled entertainment and fun facts! 
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Before my time at Back to the Sea I worked for the Petty Harbour Mini Aquarium. ​For my first interview there, I was told to bring a prop and talk about an ocean animal. I knew I couldn’t bring a live octopus, so I settled for its North Atlantic cousin - the squid! From that moment forward, it was an inky love affair. As highly intelligent creatures, cephalopods continually amaze scientists with their ability to understand, learn and even go so far as to escape their tanks! We love to do squid dissections to not only feed our animals, but also to teach our visitors all about these slimy (and at times smelly) creatures. I have been known to write squid ink letters, and maybe if you are so lucky at the Touch Tank Hut you can have one too! ​

​- Leah

Perhaps it was your colours, or maybe your jiggle,
But seeing you swim fills my mouth with a giggle,
It started off slow, with a quick glimpse of you fluttering,
But before I knew it, I heard myself uttering,
“How can anyone think you are simply a sea slug,
As if you were just another beetle, cricket or pill bug,
No, you are so much more than that, a work of art,
Something that so quickly captures my heart."
I looked at the creature once more as it bobbed and twisted,
And thought that its great qualities needed to be listed,
Firstly, unlike us it has no back bone,
Allowing it to move like a thread that has not been sewn,
Secondly, it gets its bright colours from the food that it eats,
Munching on corals, sponges, and anemones – how neat,
Thirdly, it has a foot and leaves a slimy path,
You can always find where it has been by its aftermath,
Fourthly, they can change between being female or male,
Reducing the likelihood of a reproductive fail,
And to wrap it up, a fact that is short and sweet,
One that makes seeing this animal such a wonderful treat,
The truth is that it only lives a few weeks, maybe a year,
But do not be sad, do not shed a tear,
For the facts that you learned have made you smart,
​And the love of a NUDIBRANCH will stay in your heart!

​- Kaitlin

One of my first loves has always been the ocean. Initially, as I’m sure is the case for most of us ocean-lovers, it was the faces and personalities of creatures like dolphins, whales, and turtles that caught my attention. Now, my love of ocean creatures extends past the traditionally adorable and focuses more on the absurd and unique. One species of fish that has captured my heart are lumpsuckers, specifically Pacific spiny lumpsuckers. I mean, have you seen these before? 

Whale, Valentine’s Day confession: I have a really hard time talking about just one marine creature. I mean, there are thousands upon thousands of species in the sea, many of which, we have yet to discover. One animal that I have always found particularly fascinating is the whale shark. Whale sharks are the biggest fish in the ocean. They are up to three times the size of a great white shark, yet the majority of their diet is made up of microscopic organisms, plankton! Unfortunately, these majestic creatures are endangered and are in need of a little extra love. In order to learn more about these animals and to help protect them, researchers can track and identify individuals based on their unique spotting pattern. To do this, researchers use a similar technology to that used by NASA to identify constellations in the sky. Whaley neat, isn’t it?

- Meghan

Thank you to Leah, Kaitlin, Natasha and Meghan for sharing their love for the ocean this Valentines Day. Now it's your turn, comment below to tell us which ocean animal is your favourite! 

There’s lots to see while SCUBA diving the North Atlantic coast; long-toothed wolffish, scowling eelpouts, graceful winter skates, fields of magenta coralline algae, and if you’re lucky, a glimpse of a humpback whale in the distance. In all that diversity, the sea urchins are some of my favourites – and it’s all about the hats.

​The most common urchin in Newfoundland, and throughout the Maritimes, is Strongylocentrotus droebachiensis,  a bit of a mouthful for the unassuming green urchin. We see hundreds of green urchins on every dive, and in the shallows, we find them covered with anything they can get their tube feet on: rocks, shells, even the odd golf ball.
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​​Echinodermata refers to the phylum of animals that includes seastars, sea cucumbers, sand dollars, crinoids, and our hat-wearing urchins. Echinoderms share a few key features, including a couple that sound like superheroes: Wolverine’s regeneration and Spiderman’s ability to scale smooth surfaces at any angle. We’ll get back to regeneration later on.
 
Echinoderms move around the seafloor (or simply move food to their mouth) using hundreds of sticky tube feet. These feet are part of the water-vascular system, a network of seawater-filled tubes. Urchins move using the tube feet on their ventral side by contracting small muscles that force water into the  tubefoot to take each step. The end of each tube foot is very, very sticky. They are often described as suction cups, however recent research[1] indicates that echinoderms likely use a bio-adhesive, rather than suction, to achieve their Spiderman-like climbs.

Urchins also use these sticky tube feet to pick up and hold onto rock, shells, golf balls, and other treasures.
 
But why? 

Behavioural ecologists call urchin hats “covering behaviour”. That name is related to the first and most prevalent hypotheses about the phenomena: the urchins are covering themselves to provide shelter from sunlight, predators, or both.

​Experiments conducted on Paracentrotus lividus, the purple sea urchin common to the Eastern Atlantic Ocean, confirmed the light hypothesis. Researchers in Ireland found that when the urchins were exposed to full spectrum UV light, more individuals would pick up their hats and/or move to the shady corners of their tanks to avoid harmful UV radiation[2].

​Around the same time, another scientist in California was studying covering behaviour of Pacific rose flower urchins, Toxopneustes roseus[3]. The rose urchin study wasn’t conducted in a lab; instead urchin behaviour was observed in their natural habitats. What they found was that at the sample site with the greatest wave energy, there was also the most covering behaviour among the urchins.

So which is it? Sun safety? Or are these hats more like seat belts and kneepads, weighing urchins down and protecting them from wave damage?

On this side of the Atlantic, researchers tested several factors simultaneously to trace the covering behaviour to it’s source. In a laboratory, green urchins were exposed to common predators, wave surge, waving algae blades, and sunlight[4]. As it turns out, the predators were a bust: their presence had no significant impact on the rate of covering behaviour.

​The hats are not camouflage.

Like the Irish purple urchins, green urchins exposed to UV light were found to cover up more. However, UV exposure wasn’t the most important factor. This study found that green urchins on the east coast of Canada, like rose urchins in California, wore more hats when they were exposed to wave surge, and/or in contact with moving algae blades.

Not all urchins wear hats though; the Canadian study found that smaller urchins were more like to cover up. 
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​Seastars can regenerate lost arms, sometime many at a time (see? I told you we’d get back to this). Though it’s less dramatic, urchins are constantly regenerating lost and broken spines. But regeneration takes energy. It may be a safer bet, particularly for a small urchin who is vulnerable to dislodgement and damage, to pick up some extra weight and a little sun protection at the same time. 

Emilie is a marine conservation biologist and PhD candidate at the Memorial University of Newfoundland. She is also the Chair of the Biology Graduate Student Association at Memorial. Emilie knows all about catch-and-release aquariums as she has been a volunteer scientific diver for the Petty Harbour Mini Aquarium for the past four years. t: @maptheblue

​Thanks so much for writing this post Emilie. We can only hope you'll be able to join us on a Back to the Sea dive one day! 

P.S. Another thing we love about Emilie are her awesome pictures, like this one of an urchin's mouth, known as Aristotle's Lantern. 

​People might be surprised to know that a big marine predator that kills fish using electrical  shock is coming in increasing numbers to shallow waters around Nova Scotia!

This late summer visitor is the Atlantic torpedo ray, Tetronarce (formerly Torpedo) nobiliana, a large, enigmatic member of the skate and ray family (the Batoids) found from tropical to temperate waters on both sides of the North Atlantic inshore and in deep waters. By far the largest of 17 species of electric rays worldwide, the torpedo ray can weigh 90kg and have a body disc diameter approaching 2m in mature females.

This species uses electrogenic organs comprised of modified muscle cells in the lateral margins of the body disc to generate controlled DC current bursts in excess of 200 volts. This shocking power can snap the back of a mackerel in tetanic convulsions and is also used for discouraging predators. A friend of mine who was shocked by this species while diving lived to tell the tale and likened the sensation to putting your finger into a dryer socket. 

The electrogenic tissues of torpedo rays have been extensively studied at the cellular and molecular level, with thousands of citations in the scientific literature. Some of the earliest work on the neurotransmitter acetylcholine and its effects on muscle tissue were first characterized in torpedo ray tissues. It is a paradox that despite extensive study at the cellular level, little is known of the ecology, movement and behaviour of T. nobiliana. In fact, decades of fishing for use in neuroscience research depleted local populations of this species in the vicinity of the Marine Biological Laboratory at Woods Hole Mass. 

The fact remains that virtually nothing is known about the basic biology of T. nobiliana. The size and age structure of the Atlantic population, depth, substrate and temperature preferences, onshore/offshore movements of this species, prey preferences, longevity, reproductive parameters and life cycle are all poorly known.

​The IUCN (International Union for Conservation of Nature) Red List indicates the species is data deficient, in common with the majority of sharks, skates and rays. In this respect, our knowledge of T. nobilana resembles the former state of knowledge of many large charismatic species such as sharks, tunas, sea turtles and many marine mammal species prior to the development of modern electronic tracking technology beginning two decades ago.

Like the curious case of the dog that failed to bark in the night, the fact that this species is rarely reported as bycatch despite intense commercial fishing within its known range begs the question: where do these animals go? What is their role in the seasonal summer assemblage of large pelagic and forage fish species that occurs in boreal seas around Europe and North America annually? ​​

​The habit and habitat of this species remains a mystery. Observations exist of occasional individuals in shallow water sand and mud bottom habitats from Nova Scotia to the Florida keys and from northern Scotland to West Africa, into the Mediterranean, usually from fisheries bycatch inside continental shelf depths. Fishbase and similar database sources cite depth data for this species from shallow water to 800 meters and report their presence as rare fisheries bycatch in the Mediterranean. Several references claim the rays are benthic bottom dwellers when younger and become more pelagic dwellers as they get older, but there is little evidence in the primary scientific literature to support this claim.  
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In the fall of 2015, Dr. Fred Whoriskey and myself tagged a female Atlantic torpedo ray with a satellite tag near Halifax, NS. The tag was programmed to pop up to the surface 95 days later, and report its position and other data to a geosynchronised satellite. I had theorized that the rays were following the shallow continental shelf migrations of forage fish like herring and mackerel - north in the summer and south in the winter. Imagine my surprise when the tag reported 95 days later from an offshore location over 900 km out in the North Atlantic, from an area where the bottom is in excess of 4000 m. This single record indicated that in at least one case, this species does in fact act as a pelagic animal, quite amazing for a ray we had found dug in to the bottom while scuba diving in 20 m of water.

This discovery has led to plans for a more extensive study of the movement and behaviour of this species. Volunteers interested in helping the torpedo ray tagging team can contact me at Dalhousie University: chclark@dal.ca.